Communicating Tactics

I understand a strategy for each stage is developed before the race, but certainly changes must be made during the race as things change (Mayo falling behind for instance). [I think of John Elway coming to the line and changing the play after reading the defense] If Armstrong, as the captain, makes slight changes in the strategy while riding, how does he communicate them to the rest of the team? With Ullrich and Hamilton inches away he can't tell his team to stop taking pulls or to push up the pace. Do they have hand signals they use? Or maybe he whispers in his radio and Johann then broadcasts the new plan to the rest of them team. I have to believe the poker-faced Armstrong likes to keep everything as secret as possible.

I was watching this thread for an answer and seeing none I asked cyclingnews.com and their reply was via race radio.

I asked for clarification as to whether Tyler (for example) can communicate via radio to his teammates or can he only communicate via radio with his team car. The reply was he communicates with his teammates normally. So, I assume there's just spoken dialog going on.